Vacuum insulating glass (VIG) window units typically include at least two spaced apart glass substrates that enclose an evacuated or low-pressure space/cavity therebetween. The substrates are interconnected by a peripheral edge seal and typically include spacers between the glass substrates to maintain spacing between the glass substrates and to avoid collapse of the glass substrates that may be caused due to the low pressure environment that exists between the substrates. Some example VIG configurations are disclosed, for example, in U.S. Pat. Nos. 5,657,607, 5,664,395, 5,657,607, 5,902,652, 6,506,472 and 6,383,580 the disclosures of which are all hereby incorporated by reference herein in their entireties.
FIGS. 1 and 2 illustrate a conventional VIG window unit 1 and elements that form the VIG window unit 1. For example, VIG unit 1 may include two spaced apart substantially parallel glass substrates 2, 3, which enclose an evacuated low-pressure space/cavity 6 therebetween. Glass sheets or substrates 2,3 are interconnected by a peripheral edge seal 4 which may be made of fused solder glass, for example. An array of support pillars/spacers 5 may be included between the glass substrates 2, 3 to maintain the spacing of glass substrates 2, 3 of the VIG unit 1 in view of the low-pressure space/gap 6 present between the substrates 2, 3.
A pump-out tube 8 may be hermetically sealed by, for example, solder glass 9 to an aperture/hole 10 that passes from an interior surface of one of the glass substrates 2 to the bottom of an optional recess 11 in the exterior surface of the glass substrate 2, or optionally to the exterior surface of the glass substrate 2. A vacuum is attached to pump-out tube 8 to evacuate the interior cavity 6 to a low pressure that is less than atmospheric pressure. After evacuation of the cavity 6, a portion (e.g., the tip) of the tube 8 is melted to seal the vacuum in low pressure cavity/space 6. The optional recess 11 may retain the sealed pump-out tube 8.
As shown in FIGS. 1-2, a getter 12 may be included within a recess 13 that is disposed in an interior face of one of the glass substrates, e.g., glass substrate 2. The getter 12 may be used to absorb or bind with certain residual impurities that may remain after the cavity 6 is evacuated and sealed. The getter is of or includes a mixture of metals that can react with gas(es) to hold gas(es) impurities to the gettering surface and/or dissolve such gas(es).
Disclosed herein are techniques for optimizing (e.g., increasing) the surface area of active getter within the constraints of a VIG window unit.
In certain example embodiments of this invention, there is provided a vacuum insulated glass (VIG) window unit comprising: first and second substantially parallel glass substrates, a plurality of spacers and a seal provided between the first and second substrates, a space, defined at least by the seal, located between the first and second substrates and being at a pressure less than atmospheric pressure, a getter recess defined in the first substrate for receiving an originally positioned getter, and a getter structure on the second substrate, located substantially opposite the getter recess in the first substrate, designed so that more getter material surface area is provided on the second substrate after getter activation. The getter structure on the second substrate may comprise a recess defined in the second substrate in certain example embodiments.
In certain example embodiments of this invention, there is provided a vacuum insulated glass (VIG) window unit comprising: first and second substantially parallel substrates, a plurality of spacers and a seal provided between the first and second substrates, a space, defined at least by the seal, located between the first and second substrates and being at a pressure less than atmospheric pressure, a first getter recess defined in the first substrate for receiving an originally positioned evaporable getter (EG), a second getter recess defined in the second substrate in a position substantially opposite the first getter recess so that at least a portion of the first getter recess in the first substrate overlaps with at least a portion of the second getter recess in the second substrate, and wherein evaporated and deposited getter material, from the EG, is located in both the first getter recess and the second getter recess.
In certain example embodiments of this invention, the surface of the substrate receiving the getter deposit (e.g., EG type getter), and/or a surface opposing the original getter deposit across the low pressure cavity, may be contoured so as to increase the area of the active gettering surface in the confined VIG space housing the getter. This increasing of gettering surface area at least following activation of the EG may be achieved by one or more of (i) rounding and/or chamfering edge(s) of the cut/recess in the smooth glass substrate where the EG is located so as to increase the scattering of getter material upon activation so that the EG is flashed over a larger area when activated, (ii) contouring the substrate surface receiving an EG deposit so as to increase the area of the active surface in the confined space housing the getter, (iii) roughening the area of the otherwise substantially smooth glass substrate receiving an EG deposit, such as via sandblasting, etching and/or grinding, so as to enable an increase in gettering material surface area, (iv) pre-depositing in the area to receive an EG deposit a rough (e.g., nodular) and/or porous coating, such as via sol gel or selected frit application, in order to promote porosity in the getter deposit which increases the getter's sorption capacity, (v) using EG material that is provided in a getter container that is shaped with at least one open area(s) to optimize scattering and/or evaporation direction(s) of gettering material upon activation/flashing, and/or (vi) providing any suitable recess and/or roughened coating on the substrate opposite the original getter location so as to be across the low pressure cavity from the original getter location so as to increase the area of active gettering surface on the opposite substrate following EG activation/flashing. Any or the above embodiments/features (i), (ii), (iii), (iv), (v) and/or (vi) may or may not be used in combination with any of the other embodiments/features (i), (ii), (iii), (iv), (v) and (vi) in different embodiments of this invention. For example, embodiment/feature (i) may or may not be used in combination with any of (ii)-(vi) in different embodiments of this invention. Thus, the getter recess and/or a getter container in the getter recess is/are shaped to increase evaporated getter material surface area, with evaporated getter material being the getter material that is present after activation and/or flashing of a getter that included EG type material.
These and other embodiments and advantages are described herein with respect to certain example embodiments and with reference to the following drawings in which like reference numerals refer to like elements throughout the several views, and wherein: